A couple things have helped me in dieting:

– Keeping a “food/exercise diary” recording everything you’ve eaten, the exercise you’ve done that day, as well as your weight, waist measurements and body fat percentage (I’ve got one of those scales that does the latter). The point is not to obsess over what you’re
eating, but it’s great way to make you conscious of what you’re eating and how much you’re exercising. It helps prevent absent-minded snacking and blowing off exercise. As far as recording your weight, etc. it may not be for everyone, but it works well for me. I don’t
obsess over minor fluxuations in weight/body fat, since those can be affected by how hydrated you are, but if I’m consistently up or down for a couple days in a row I know there’s a change going on. (I don’t count calories, but just try to eat better, eat less, so sometimes I’ll go up a bit or just plateau, which tells me I need to change my behavior if I want to keep going down.) – Employing the principle of satiation, i.e. often times craving can actually be satisfed in a few bites. Unfortunately, we typically eat far more than that. But if you’ve got the will-power it’s good way to feel like you’re still eating normally. For example, I’ll have a
tablespoon of Haagen Daaz chocolate ice cream, savor it and then put it back in the freezer. Yeah, it’s caloric but in such small quanties you can easily compensate. I’ve also used this to head off snacking. I’ve found Pepperidge Farm’s butterthin crackers to be really useful because they’re quite rich and eating a single one is enough to trick
my body into thinking it’s been feed more than it has. But a single cracker isn’t a lot of calories. A small slice of strongly-flavored cheese, like parmasen regiano, works well too. – Having a “free day.” This can work in two ways. First if I’ve got a craving for something really caloric, say pizza, I tell myself I can have it if I wait until Saturday. Most of the time
when Saturday rolls around, the craving has passed. Second, there was a site I ran across by a personal trainer who’s done a bit of work with transsexuals who were doing some very hard-core dieting. She found that easing up a bit on the weekends not only made the dieting much easier psychologically, but also seemed to prevent the body from going into “starvation mode” and slowing down the metabolism.